I carry a STEAL pistol.
The finish on aluminum is thin and not durable (from my experiences). I would say that the issue with your feed ramp is cosmetic. Bullets are made out of lead, or copper, both of which are softer than aluminum.
Practicing with your carry gun is a good idea. The aluminum guns are nice for carry because of weight, but not practical in terms of taming recoil like a steal pistol or using the weapon as a club. Follow up shots are a plus.
Keep your eye on the frame where the slide stop inserts. Aluminum guns tend to crack there first. I think its safe to say steal pistols can obtain service lives of 100,000 rounds, and many out there nearly 100 years old, are still functioning. Aluminum guns - depending on if you're shooting hot defensive loads, or light target loads - can be found to start stress cracking at around 25,000 rounds.
Ball ammo or hollow point ammo wouldn't make a different.